Echoes
by Zea T
Summary: New discoveries can bring to life echoes of times past. The only choice is whether to fear the memories, or embrace them. Bluestreak, Jazz and Prowl have to make that choice - sequel to my earlier fic 'Fall'.
1. Remembering Times Past

Title: **Echoes**  
Author: zea_taylor  
'Verse: G1, sequel to 'Fall'  
Rating: T/PG-13  
Characters: Jazz/Prowl, Bluestreak  
Warnings: angst, fluff

Summary:  
_New discoveries can bring to life echoes of times past. The only choice is whether to fear the memories, or embrace them._

Author's Note:  
_Written for the _****prowlxjazz ****_community's Anniversary Bingo Challenge. Each chapter is inspired by one prompt, posted by _****wicked3659****_. I think this is the last of that set that I hadn't got around to uploading here._

_Thanks, credit and acknowledgement also go to _****whitefirebird****_, who suggested this premise in a comment on my earlier fic '__Fall__,' and was kind enough to beta it. This sequel is set many vorns later, after the Ark arrives on Earth._

_Comments and suggestions for improvement are always very welcome!_

* * *

_**Part One**_

_**Prompt: remembering times past**_

"You know, maybe this was a bad idea."

Bumblebee's voice echoed off the low rock ceiling. The reverberations ebbed and flowed, scattered by the stalactites plunging down from above and the stalagmites that rose to meet them. They rippled along Bluestreak's door-wings, the sensation jarring and a little uncomfortable.

Drawing his sensory panels in close to his back-plates, the young sniper tried not to look too relieved at Bee's realisation.

"Y'know I was just thinking the same. It's always kind of nice to spend time together, Bumblebee, you know that, and it's not like there's anyone else our age on the Ark, not really, so it's great to talk when we get the chance and it did seem like a really good idea to explore down here for a change, rather than going out in the rain, but it's cold and it's dark and it's kind of quiet down here and… and _I really don't want to be here_."

That last bit escaped before Bluestreak could filter it. Even by his own standards his speech was excessively fast. His door-wings were twitching too, enough so that Prowl would frown if he were here and chide his protégé for not staying in control.

The sidelong look he got from Bumblebee told him that his nervousness hadn't gone unnoticed. The yellow minibot tilted his helm to one side, one servo coming up to rub a stubby helm-horn.

"Hey, Blue? Are you okay?"

"Fine, I'm fine. Really. I'll be okay."

He really wasn't fine. Exploring the cave network under Mount St Hillary had seemed like a fun idea, but every breem Bluestreak spent underground was making him more unsettled. The climb down through the Ark's lower decks into the caverns below had been enough to trigger the feeling. There was something about the darkness, the sense of weight above him and the silence down here that was doing bad things to his processor. It was like there was a memory file jamming his recall unit, not quite accessible, but not clearing to let other information past. He felt that there was something he should remember, but at the same time was quite certain he didn't want to.

He cycled his optics down, trying to tune out his surroundings. Bumblebee was a good friend, but more than anything Bluestreak wanted to talk to Prowl. Or Jazz. Jazz would be good too. The two of them were used to his freak-outs. They'd listen and not judge, and Jazz was always good for a distraction or two. Bluestreak could use one right now.

Neither of his mentors would take him at his word, as Bumblebee was doing now. He could hear his friend strolling across the cavern floor, kicking idly at loose stones as he went.

"We'll head on up in a klick or two, okay? I just want to take a look over he…arrrgghh!

Blue cycled his optics back online in a hurry. His door-wings flared wide, their tips scraping the rock columns around him as they searched. Bumblebee had been somewhere on the far side of the cave they'd stumbled across. Even if Bluestreak's optics had been online, his friend would have been hidden from view by twists and turns of the rock.

His own discomfort shoved aside, Bluestreak hurried forward.

"Bee? Bumblebee, are you all right? I hope you're okay because it wasn't easy to get down here, and it'll be real tough to get you out if you can't walk, or have broken a strut or something. I might have to call Ratchet down here, and I think he'd be pretty annoyed because…"

"Blue! Watch out for – "

For the second time in as many minutes, Bee's words cut off in a shower of falling pebbles and the sound of a mech hitting the ground.

Bluestreak didn't hear the echoes of his own fall as they swelled and then faded. The ground had opened beneath his pedes, the sudden sharp drop plunging him into darkness and a deeper cavity below.

_Falling. Darkness. _

The memory file straining his processor was still hazy, its context unclear, but the emotional resonances it carried broke through the block.

_Terror._

"Bluestreak? Come on, Blue buddy, talk to me."

For a microklick, as he sought instinctively for comfort, he thought it was Jazz talking to him rather than Bumblebee. Either option was wrong. It was Prowl's voice his processor was searching for, and which Bluestreak longed to hear. Prowl was the one who'd kept him safe, and held him when the world dropped out from under them.

He shuddered. His door-wings folded tight in against his body, his entire form huddled where it fell. He knew now which memories were stirring. And he knew he didn't want to see them any more clearly.

Clenching his servos into fists, Bluestreak shook his helm. No. He didn't have to let the nightmares take control. Prowl had always told him that, and his faith in his guardian was never less than a hundred percent. Darkness wasn't his friend, but darkness could be banished.

"Whoa." Bumblebee took a few steps backwards on the uneven surface as Bluestreak turned on his headlamps. Both mechs' optics cycled, flaring and dimming as they recalibrated for the illumination. A few klicks later, Bee lit his own lights, adding to his friend's as both stared around them.

"Whoa," he repeated, his vocalisor softer this time.

"Oh wow!" Bluestreak echoed, for once all but lost for words. "This is… this is… amazing!"

The cavern wasn't all that big – perhaps twice as tall as Bluestreak and about the same across – but if anything that just magnified the impact of it.

Every wall of the spherical cavity was coated in angular crystals, some just inches long, others rivalling Bumblebee in height and width. They grew from every wall, angled in towards the centre of the cavern, regular where they had space to grow, tussling with their neighbours where the limited room required it. Most were hexagonal in cross-section and translucent – ranging from almost transparent to a milky white. Here and there, colours rippled through the crystal growths. The most common tint was a vivid purple, but Bluestreak's headlamps picked out blues and greens, yellows and even a few glimmers of dark red, deep within the crystalline array.

"Huh, well this is kind of pretty." Bumblebee acknowledged the sight, assessed it and dismissed it with a single phrase. The yellow minibot was already turning back towards the opening they'd fallen through. "I guess if the crystal edges aren't too sharp, we could climb up…"

Bluestreak hadn't got that far. He was still looking around the huge geode with wondering optics. It seemed almost sacrilege to be thinking of escape – a rejection of something beautiful and precious that Primus had given them. He wasn't watching when Bumblebee gave a metre-long shard a solid thump, testing its edges. He heard it though, and felt it too. His door-wings flinched and then angled of their own accord towards the source of the sound. A shiver ran through him, the sensation not entirely unpleasant. Only now did he realise what he'd been sensing since the moment he fell into the cavity – the reverberations, triggered by his impact, that refused to die away.

Maybe it was his uneasiness in the dark caves, the terror of his fall and the memories it brought too close to home, that made the mental connection. He reached out with a tentative servo, tapping the nearest crystal and spreading his door-wings to catch the vibrations. This didn't just feel right. It felt familiar.

"Prowl." He whispered the name aloud, puzzled. For some reason this place was making him think of his childhood guardian, and of music, and that didn't make sense at all.

It was connecting with something else too. Bluestreak didn't know the names of his original genitors. He had precisely one image of the mechs. The memory capture – of a squirming grey mechling in the arms of his laughing guardians – had been on his berth-side table as far back as he could remember. He'd dithered, over the years, between loving the image and hating it for the turbulent, terror-filled memories it provoked. It had never occurred to him before to think about the background, and the immense crystal outcrop behind the family group.

Looking around him now, Bluestreak wondered for the first time what it must have been like to have those crystals towering above him. With the trapped air throbbing on his door-wings, and his optics cycling to capture the sparkling light, he felt almost as if he was back in their arching embrace.

A sharp crack filled the air: the sound of glass-like quartz fracturing under a minibot's sturdy weight. At once, Bluestreak's fragile memories reverted. His door-wings folded in, tight and rigid as he tried to shake the sound of shattering crystal, and of keening cries in the darkness.

"C'mon, Bluestreak!" Bumblebee was naturally a cheerful mech, but there was a note of strain underlying his hearty encouragement. The minibot was almost at the broken entrance now, reaching down to offer his friend a servo. His bright optics were fixed on Bluestreak's faceplates, and Blue knew his oscillating mood hadn't gone unnoticed. "Let's get back to the Ark, okay? Prowl's got to be kind of wondering where you are by now."

It took an effort of will for Bluestreak to accept the proffered hand, and start to climb. This place was as intriguing as it was terrifying. He heard Bumblebee's vents cycle in a sigh of relief when he finally moved. Both mechs climbed with care now, placing their weight to avoid the smaller, more fragile, of the crystals forming the geode. Neither spoke any more than they needed to – Bluestreak exhausted and confused by his turbulent emotions, Bumblebee wary of triggering an outburst he wasn't equipped to deal with.

It took the better part of five breems to get back to the Ark. Bluestreak managed a quick "that was fun, well, sort-of anyway, and we should see each other again soon, and I don't just mean on duty, but let's go outside next time, okay, and I've got to go find Prowl now, so I'd better go this way, and I'll see you later, and bye for now!". Bumblebee grinned, rubbing his helm-horn just hard enough to betray his concern. Bluestreak would go find him later, when he understood himself, and try to explain. For now though, he hurried through the Ark, heading for the command corridor and knocking on his mentor's office door with more than his usual urgency.

"Prowl, are you busy? I hope you're not. I really want to see you, and, well I kind of think I _need_ to see you, because 'Bee and I found the most wonderful thing and the strangest thing. I… I don't know what I…."

The office door slid open without further ceremony. Bluestreak tumbled through, the explanation starting almost before his former guardian locked the door behind him.

Prowl's optics shone with concern; his door-wings flared wider than their accustomed stern angle. He listened to the stream of explanation from Bluestreak with a frown and no more than occasional words of encouragement or comfort.

It was a breem before he rounded his desk to take the youngling he'd raised in a brief but spark-felt embrace.

It was another two before Bluestreak finished talking, perched on the desk with his mentor close beside him. Prowl stood. He reached out a servo towards Bluestreak, drawing the younger mech to his pedes. Bluestreak obeyed the silent command without hesitation. His guardian's expression was calm but Prowl's door-wings trembled a little.

"Show me," was all he said.


	2. Secrets

_**Part Two**_

_**Prompt: secrets**_

If anyone else were around, Jazz would never have allowed his pensive frown to show. Alone on the control deck, he scowled in earnest. His visor stayed locked to Teletraan-1's readouts, but his attention was elsewhere. Watching on his internal screen, he bit back a groan as Prowl's status signal switched from "on duty" to "available if required" and then straight onwards to "not available". The first of those transitions was usual for his companion, if rather prompter than normal. The second was less so.

This was the sixth time in under an orn that Prowl had absented himself from the Ark immediately after his shift ended. Bluestreak didn't maintain the same online status as the officer corps, but Jazz knew without checking that the youngling he'd helped raise would be gone too.

The slagging thing was that he had no idea where they were going.

Secrets bothered the Ops mech on principle. Too often, playing the spy game, you could be the best there was and it would be the one thing you hadn't figured out that killed you. Jazz _was_ the best. He intended to keep that title, not to become an object lesson to the mechs under his command.

There was more than that though. Secrets bothered him, but it was the fact that this was Prowl and Bluestreak – the two mechs he was closest to on this planet or any other – that was really upsetting. He and Prowl had shared their quarters, their berths and a deep mutual affection for vorns – at least half that time with a very young Bluestreak in their mutual care. It wasn't like either Prowler or Blue to be secretive, or to exclude Jazz from any aspect of their lives. He wasn't sure what was more hurtful – the fact that Prowl was keeping him in the cold, or that his partner of vorns' standing didn't even seem to have noticed Jazz's sense of rejection.

Meeting his own visor, reflected in the monitors, Jazz grimaced. He was being selfish. Prowl was focused on Bluestreak, that was all. It felt churlish to resent that focus. The young mech had come back from his excursion upset enough that Jazz was worried too. Bumblebee didn't seem to know why, and had just shrugged under Jazz's careful inquisition, reluctant to tell tales on his friend. He'd said enough for Jazz to fill in some of the gaps but by no means all.

Bee's description of the cold dark spaces beneath the Ark rang uncomfortable bells for Jazz too. He still woke from recharge with nightmares, his processor conjuring images of Prowl and Bluestreak falling into the depths of Cybertron. He knew that both mechs shared his disrupted recharge, even if the disturbed orns were far less frequent than they had been in times past. Small wonder that the expedition with Bee had reminded Bluestreak of the traumatised mechling he'd once been.

It still frustrated the saboteur that even if had a fair idea about what caused the upset, he had no idea what Prowl was doing about it.

"Jazz."

Jazz startled upright in his seat, his visor polarising to conceal the reaction. Man, he really was bothered if Optimus Prime could sneak up on him. The big mech always did move quietly for his size, but to find him stepping out from behind a stalagmite was still a bit of a shock.

"I am glad to have caught you alone, Jazz. I rather wanted to talk to you."

Jazz grinned, covering his surprise, and swung the monitor chair idly from side to side.

"I'm all yours, boss." He waved a hand to take in Teletraan's terminal and the large screen that dominated it. "Not like I can run away from you. Monitor duty." He cycled his visor in an equivalent to the human wink, shaping his faceplates in an exaggeratedly mournful expression. "Someone's got to do the dirty jobs."

Prime's optics brightened a little, amusement showing behind his blast mask. He looked from side to side, checking their surroundings. Automatically, Jazz did his own quick recce.

The Ark's control deck was empty apart from the two of them. The crashed ship wasn't the most comfortable of homes at the best of time, and the control deck wasn't somewhere a mech wanted to linger. The Ark would never lift off from this world, or return them to their distant home. The organic dust and carbonate rock columns littering the command deck were a reminder of that sometimes-painful fact. Jazz didn't blame the crew for spending more time in the Rec Room, or their quarters, or even out exploring the mysteries of their new world. Truthfully, he'd rather be doing the same himself.

That or tracking down a different kind of mystery.

He forced that line of thought to one side. Raising a brow ridge, he adjusted his visor with one servo, and turned an inquisitive expression on Optimus Prime.

"So, what's up, boss?"

"I was wondering if Prowl has spoken to you about these frequent absences?"

So much for shaking off the thought. He kept his voice neutral, shrugging.

"The vorns we've spent trying to persuade the mech to take some real down-time, can't really blame him for doing just that."

The same chagrin Jazz felt showed in Prime's optics.

"Prowl is, of course, free to spend his off-duty joors in any way he sees fit, but…"

"But…?"

"I must admit to a certain curiosity."

Jazz hesitated, reluctant to make the same confession.

"I asked," he admitted finally. "He said it's a Praxian thing, Optimus." He cycled his optics with exaggerated patience, trying to make light of the mystery. "Then changed the subject on me."

The sudden upkick in his friend's engine note spoke eloquently of Prime's reaction to the comment. Praxus. Prowl and Bluestreak's home city. The greatest failure in Autobot history. The city's fall marked the moment that the uprising escalated, from a clash between well-defined factions, to a total war that would touch every spark on Cybertron.

Prowl had never made a big point of being Praxian, not since escaping the tragedy. He'd raised Bluestreak in what he could of their traditions, but Jazz had grieved with him at how little was left. Of course, it wasn't as if _any_ of the city-states had managed to save much of their ancient culture. Praxus had burned first, but it hadn't been the only city to fall. Now their whole planet was gone, its war-ravaged surface lost to them entirely.

But … Praxus _had_ died first, and that day would never stop haunting those who'd lived through it.

Prime vented a sigh. The big mech folded his arms across his chest-plate, his expression thoughtful.

"Nonetheless, Jazz, I know of at least three mechs who have attempted to follow Prowl or Bluestreak. All have failed."

That, at least, got a smile out of the saboteur.

"Prowl ain't big on hangers-on."

"Prowl has been my lieutenant for vorns." Prime hesitated. "This sudden secrecy is not like him. It… troubles me."

There wasn't much Jazz could say to that, short of echoing his Prime. Optimus seemed to be waiting for some kind of response, but Jazz had learned self-control over the vorns. He held his silence, forcing Prime to take this conversation wherever it was going without his help.

Prime's hopeful expression faded, and Jazz would swear he saw embarrassment on his friend's face.

"I was wondering if _you_ might consider…?"

There was a long pause. Jazz knew the humour had drained from his faceplate, along with the relaxed mask he showed the world. His expression was utterly serious as he pushed out of the monitor chair and stood in front of his Prime.

"You're asking me to check on them and report back?"

"Well…"

"Do you actually think Prowl and Bluestreak are doing anything against the rules? Anything wrong?"

"What? No!" Prime's immediate, startled response earned him back a few points in Jazz's book. It didn't and couldn't excuse the request.

Jazz held Prime's optics for a long moment, his expression hard. He shook his helm with a firm, decisive motion.

"Then let's get one thing slagging clear, Prime. I won't spy on law-abiding Autobots – least of all Prowler and Blue – not for you, or anyone."

If Optimus Prime was surprised by the rebuke, at least he had the grace to accept it. His engine grumbled uneasily, his servos spread in front of him, open in a show of acknowledgement and regret.

"I didn't mean…"

Jazz snorted. "Yeah, you did." He dropped back into his seat and sprawled casually across it, letting Optimus off the hook. The saboteur's fingers drummed against Teletraan-1's console, his expression still creased in a small frown. He pushed against the floor, his chair spinning through a full three-sixty, before glancing over his shoulder at his Prime. "Which isn't to say I might not go take a look – just for my own peace of mind, you know? Prowl's being pretty crafty though. He's got us on swing shifts and by the time I'm free to go hunting, he and Blue are back."

Optimus Prime's optics brightened. His engine note was still a little coarser than usual, his processor stung by Jazz's response. It calmed, a deliberately nonchalant expression crossing his faceplates.

"I have some paperwork to do this morning, Jazz," he said in a voice so casual it screamed subterfuge. "I can do it here as well as anywhere else. I was wondering if you'd like me to take over the monitors a few hours early? To 'kill two birds with one stone' as our human companions say."

Jazz cycled his optics, amused despite himself. There was more than one reason why Optimus had never trained for Special Ops.

Shaking his helm, in amusement rather than refusal, he stood. "You know what, Optimus, that sounds like a really neat idea. It's all yours."

* * *

The trail was almost three breems old.

Knowing Prowl as well as Jazz did, that meant a breem to leave his office, stop by their quarters and collect Bluestreak, and most of a second to ensure he weren't followed before leaving the Ark. That left Jazz maybe ten minutes behind. Not a bad gap. He could work with it.

He moved through the Ark quickly but without letting his haste show. The smiles and greetings he exchanged with Hound and then with Sunny and Sides were brief, Jazz's demeanour giving the impression that he was heading off to meet someone else without his ever having to commit to the lie.

It wasn't until he hit the lower decks that he slipped properly into a Special Ops mind-set. He started to move cautiously, his senses alert for any hint of monitors or laser trip-wires. He wouldn't put it past Prowl to set them. The tactician had been around Jazz long enough to pick up more than a few unconventional habits, and that was on top of his own Praxian enforcer training.

The bottom decks of the Ark were a mess. They'd borne the brunt of the ship's impact so long before, and taken most of the strain as the ground heaved and shifted through four million years of volcanic activity. The result was a folded, corrugated maze. Some corridors were twisted like the walkways in a fairground crooked house. Others seemed perfectly normal until you realised that their ceiling and floor grew steadily closer, creating a false perspective you didn't notice until your helm brushed the metal plates above.

It didn't help that this part of the ship was well below ground level. Okay, it was still enclosed, for the most part, by the outer hull, but it still felt like the deep and empty places of Cybertron. No one ventured below the surface of their home planet by choice. Theirs was a world of towers, reaching for the perpetual darkness of the skies, and of aerial bridges flying high above a gnarled maze of abandoned structures. The depths were a place of nightmares, the denizen of desperate empties or the setting for cautionary tales for infants.

The Ark's own depths were just a mirror of their homeworld's. A few of the rooms down here were used for storage, but most were abandoned as uninhabitable. It must have been months since anyone came down here on a legitimate errand. The all-pervasive dust of their adoptive world lay thick on the floor, and rained down from ledges and doorframes if knocked… which made the trail of pede-scuffs and compacted dirt something of a dead giveaway.

Relatively few of the pede-marks were Praxian in form, and most of those probably came from Bluestreak. Jazz's sharp visor identified and cross-matched signs of Bumblebee too, and of the Twins and even Tracks – the last three on fruitless attempts to follow their second in command.

Bumblebee had told him enough about his first trip for Jazz to be unsurprised when the dust-trail led through a rent in the hull and into the cave network that honeycombed Mount St Hillary's volcanic flanks. He was equally unsurprised when it petered out a few yards later amidst hard natural floors and the scatter of rock shards that littered them.

Now the real work began. It was a while since Jazz had tracked a target in earnest. He dialled up his sensory network and muted his own vents, doing all he could to soak in information from his surroundings without adding to it.

His helm horns vibrated, picking up wisps of disturbed air and the faintest traces of heat. His audials picked out sound after sound – the breath of the living rock. He could hear the trickle of water, still percolating through the slopes after rainfall two weeks earlier. He felt the thumping movement of mechs in the Ark above and, deep below, the rumble of magma refilling the vast chamber at the volcano's heart.

There was another whisper of sound in the caves too, echoing and distorted until impossible to decipher. Jazz followed it, blending it in his processor with the input from his other sensor systems.

Something had passed this way: something warm and alive, and large enough to disturb the air around it. The ghosts of fading echoes carried a familiar note.

For vorns, Prowl's voice had been the first thing Jazz heard on waking from recharge. As often as not, Bluestreak's was the second. Jazz's sensitive audials would recognise those two voices against the thunder of battle or the howl of an acid storm. He followed them now, as best he could, tracing the faintest of reflected sound, doubling back when he needed to, keeping his sensors alert for the heat traces left where one mech or the other had brushed against a stalagmite or even against the low ceiling overhead.

He was perhaps half an hour out of the Ark when he paused, tilting his helm. His visor flared and then readjusted, a frown forming as he tried to interpret the new sensation. His horn helms were reacting to… something. There was a vibration in the air unlike any Jazz had ever felt. It rose and fell in pitch, the different notes blending and combining in a manner that could only be under intelligent direction. The sound was still quiet, but Jazz could feel it swelling, the individual notes becoming more distinct as he listened.

He rubbed his helm with one servo, trying to ease the pressure in the nearest sensory horn. It wasn't that the sound was uncomfortable as such. Just so very, very different from anything he'd heard before.

It was light, ethereal, and somehow grounded at the same time. Jazz was following it now, rather than the faint traces he'd been tracking before. He felt drawn towards the source, and knew instinctively that he'd find what he was looking for there.

The vibrations rose through the floor of a large cavern. Jazz wandered through the space, between columns where stalagmite and stalactite had met and merged. In places, gaps and hollows in the rock formed natural dishes, amplifying the sound. In others, the vibrations were softer but clearer, each note ringing with precise clarity. He paused, his helm tilted to one side and the breath catching in his vents.

There was nothing random about this melody. The individual chimes followed a sequence, and it was one Jazz knew. He found himself humming along, his thigh speakers throbbing gently, almost too soft to be heard.

The sudden, jarring discord came as a shock. He shuddered, a small cry of distress escaping him as the complex blend of sound collapsed into chaos. He wasn't alone in his dismay.

"I'll never get it!" Bluestreak's vocalisor was staticky with frustration. Jazz didn't have to see the youngling to know his expressive door-wings would be spread wide and his optics bright. "I'm _never_ going to be any good at this."

"Never say 'never'." Prowl's voice was calm, amused, and Jazz heard the warm affection there. "You will be perfect. But perfection takes time, Bluestreak. Be patient with yourself."

"Perfect?" Blue didn't sound convinced. "I hope so, but I don't know if I'll ever be as good as you are, Prowl. I really just want to be good enough, you know, before we do this for Jazz. I want it to be just right for him, because he'd love this, and he really ought to hear it done right, and I really want to do it well for his sake."

Jazz stifled his gasp before it could escape. He shook his helm, not sure whether he was more bemused or touched by the unexpected sentiment.

"I know." Was that amusement in Prowl's voice? "Although I suspect we have less time than you would prefer."

There was a faint chiming noise. A mech had taken a careful step, his pede striking some form of crystal as he moved. Jazz drifted forward, intrigued by the echoes, searching for the entrance that would take him to the small chamber that must lie below.

Prowl vented, the sound a little deeper than Bluestreak's systems. Jazz heard a rising hum, shaped as he listened into a deep and resonant chord, and wondered just what the Praxian was doing to produce it.

"Now," Prowl said, voice patient, "let's go through this once more."


	3. Music

_**Part Three**_

_**Prompt: music**_

There was nothing 'natural' on Earth that felt less than alien to the Cybertronian children of Primus. Of everything Prowl had seen though, this came closest to being familiar.

It had started out as a bubble of volcanic gases, rising through molten rock. The traces of those gases lingered in the near-perfect spherical cavity they'd left behind. Water had infiltrated over eons, and tiny seed crystals in the silicate-rich solution had grown into shafts almost as tall as a minibot. As they did, they'd absorbed traces of sulphur and magnesium, of iron and this world's all-pervasive oxygen. Prowl's door-wing sensors could identify and classify each element and the vivid compounds they formed. His optics revelled in the iron-tinted amethysts and golden citrines, the magnesium-rich garnets and hints of aluminium oxide sapphires nestled amongst the crystal-clear quartz.

When he'd first seen it, the wonder had been mingled with just a tinge of disappointment. On Cybertron, crystals had grown in proud spires, warmed from below by the spark of Primus. Here the energy source was far more mundane – literally 'down-to-earth'. A geode like this, with jagged crystals under-pede and others brushing Prowl's extended door-wings, simply couldn't form outside of the pressures of subduction and construction, continental drift and volcanism. There had never been anything quite like this on their home-world.

As they had been for Bluestreak though, the parallels were close enough to trigger long-suppressed memories.

The vast outcrops of the Praxian Crystal Gardens overlaid the geode in his processor. Only Crystal City itself had ever rivalled them, and there the growth had been constrained, managed and regulated. The Gardens of Praxus had grown wild. Outcrops had tussled for space, forcing paths to meander around them and sometimes even to pass through arches of pure refracted light, formed by the crystals meeting high overhead.

He remembered being surrounded by crystalline beauty, led into the heart of one of the largest outcrops as he learnt to coax it into ringing music. He remembered his first encounter with Bluestreak too, could almost feel the tiny mechling's servos in his own, gliding across the smooth surfaces.

And he remembered the sound of shattering, the thunder of the bombardment and the scream of living crystals smashed to dust.

Small wonder, then, that this place triggered echoes of his protégé's infant trauma… and small wonder that Prowl was determined to overcome that barrier and return to Bluestreak the traditional skill that should have been his all along.

As long as they let their fears dominate, they would never be able to move on from that day, either one of them. The Decepticon assault had stolen so much. Prowl was determined that it wouldn't steal this opportunity too – perhaps the only chance Prowl would ever have to teach his charge their native music, or Bluestreak would have to learn it. He'd told Blue as much on the first day they'd come here. The youngling had looked uncertain, but the strong spark Prowl had nurtured since infancy came to the fore. Bluestreak would learn. Prowl would teach, standing one more time in the stead of the genitors Bluestreak barely recalled.

On that first trip, priming the geode for music had taken hours. His skills had been rusty from disuse. Even after he recalled the long-buried memory files, there had been a steep learning curve. Finding the resonances and vibration modes of the geode was like learning a new language without a translation module to ease the task. The structures were very different from any he'd seen before. Their composition, shape, orientation and substrate all played a role in determining their response, and he had to learn each in turn.

Tapping individual crystals with precise movements, running a gentle servo over others, all the time angling his door-wings to best gauge the cumulative response, he'd explained what he was doing to Bluestreak in a soft, even tone.

The youngling's fear hadn't faded. It probably never would. Flinches and small half-frowns betrayed errant memories – of Praxus, of his genitors and of the day they fell. Prowl had watched proudly as Blue adjusted nonetheless, letting the wonder of the experience and confidence in his mentor give him courage. Blue's door-wings were angling on their own within breems, following the rhythms before Prowl could prompt him. The young mech's attempts to develop the sounds became smoother and more confident, without the trembling that marred his earliest attempts.

It didn't take so long for Prowl to prepare today. He gave one last crystal a tap, carefully timed to reinforce the vibrations and echoes he'd already developed. The whole geode hummed with stored energy, no one note dominating but each adding to the underlying murmur of sound. Now the geode was primed, it would take only the lightest of touches to raise a chosen note above the background, or still another, changing the murmured chord.

He nodded to Bluestreak, his smile encouraging his student and reassuring him at the same time. Bluestreak vented hard, his optics dilated and bright with concentration. His door-wings twitched once and then settled, spread wide to maximise their input. As Prowl stepped carefully to one side, Bluestreak moved to the heart of the geode, raising a servo to a crystal at helm-height and giving it a tentative touch.

The vibrations grew, blended, beat in synchrony and asynchrony, following the pattern that Prowl had guided Blue through with infinite patience. Any Praxian music was complex, unique to the outcrop where it was played, but this was a basic melody, commonly used to underlay the complexity. It was a simple thing – a piece most Praxian younglings would consider below their dignity to demonstrate on those long, bored evenings in the Gardens. For an absolute novice, coaxing rhythms from the silicate crystals of an alien world, with only the anguish in his spark and a few joors tuition to guide him, it was a remarkable achievement.

Bluestreak was half-way through the composition when Prowl's sensitive door-wings picked up new vibrations coming from the cavern above. With his door-wings extended and senses attuned, he could hardly fail to recognise the rhythm of familiar pedes. Careful not to let his surprise show, he shifted, the slight movements enough to counterbalance the outside influence without distracting the intent youngling.

A breem later, when Bluestreak's careful work faltered and a jarring discord between two arm-length crystals set their door-wings vibrating, Prowl's audials were already listening for the faint cry of dismay that floated on the still-throbbing air.

"I'm _never_ going to be any good at this!"

Bluestreak was already better than he thought. The same potential Prowl had glimpsed in a tiny grey mechling was there in his servos. Blue was warm and loving and more sensitive than he gave himself credit for. Growing up in the flames of unending war had given him a hard shell, just as it had Prowl and Jazz. He'd overcome that, Prowl was sure, given time and practice.

Reassuring him of the same required no false praise, only the warm affection Prowl, as Bluestreak's commander, could seldom afford to show. Blue's earnest answer only strengthened that affection.

"I really just want to be good enough, you know, before we do this for Jazz. I want it to be just right for him, because he'd love this."

There was no doubt of that.

Prowl suppressed a chuckle as he moved. He nudged a crystal with one pede, reviving the fading echoes and working to rebuild the resonant background hum that was always their starting point. Blue vented a huffed sigh, determination written in the way he squared his shoulders and set about helping Prowl resettle the geode.

For the dozenth time, Prowl guided his protégé through the sequence before stepping back and doing his best to minimise his presence. Again, there was movement above, stealthy and cautious but coming ever closer to the geode's single entrance.

"Dim your optics, Bluestreak." Prowl murmured the instruction as Bluestreak started again. "Just let your sensors guide you, and your servos follow your spark."

The blue glow that formed their only illumination dimmed as Bluestreak followed his instructor's advice. The youngling remained blissfully unaware as the fainter light of Prowl's optics was joined by a new glimmer – a polarised visor peeking through the narrow aperture.

Jazz's expression was wondering and almost dazed. The mech's helm moved of its own accord, tilting from side to side as his sensory horns gave him a hint of what Prowl and Bluestreak's wings fed through their entire frames. The mech was enraptured, distracted out of his usual caution.

Prowl met his companion's visor with amused optics, and got a surprised, rueful and not-quite-guilty-enough grimace in response. A flick of his servos to signal 'wait' and Jazz froze in the opening, even his vents baffled to avoid disturbing the youngling they'd raised.

Both Prowl and Jazz braced, their frames tense as Bluestreak approached the point where he'd hesitated before, and the rhythm had broken. This time, he managed the transition smoothly, a small sound of satisfaction escaping him as he achieved the tricky, syncopated harmony he'd been trying for.

It took a full four breems to complete the sequence. The harmonies built as Bluestreak managed the echoes and fed new taps or caresses in to strengthen fading notes. By the climax, the whole geode was ringing with sound, streaming in steady waves through sensors and processor, and warming the sparks of all three listeners.

Blue held the last note for a near-eternity, letting its echoes mingle with the long, satisfied exhalation from his vents. His optics brightened, his servos clenching in his delight as he turned to Prowl.

"I did it! I really did it!"

"You did," Prowl stepped forward, wrapping Bluestreak in a brief embrace. It was an indulgence he'd seldom allowed himself since his charge formally joined the Autobot ranks. The youngling's engine purred with satisfaction, pride and joy at the unusual display of affection from his mentor. "You did well, Bluestreak." He raised his helm, looking over Bluestreak's shoulder and allowing a smile to greet his partner. "Don't you think so?"

Jazz transformed one servo, releasing his grappling-line. A flick of his wrist hooked it over a convenient stalagmite. Twisting the line around his wrist, the Ops mech dropped into the spherical cavity so lightly that his pedes barely made a sound against the crystalline floor.

It was tight in the cavity for three grown mechs. That didn't bother Jazz. He threw his arms around both Praxians, tugging them almost off-balance with an exuberance that Prowl suspected was entirely deliberate.

The saboteur's rich laughter echoed off the crystal shards, the reflected sound fracturing until it seemed that every glinting surface was joining the joyous chorus. Jazz tilted his helm until he could see Bluestreak's faceplates.

"Sounded pretty near perfect, mech."

"Jazz!" Bluestreak's expression was torn between dismay and his lingering pride. "You're here! Why are you here? And do you really think so? I wanted it to be a surprise, and I guess it kind of was, but I had all kinds of plans and I wanted it to be just right for you, and it was _meant_ to be a secret."

For a moment, just a moment, the expression on Jazz's faceplates faltered. A mech who knew Jazz less well than Prowl would never have seen the hesitation. Even Bluestreak seemed to have missed it. The glimpse into the inner mech came and went within microklicks, and then the familiar grin was back firmly in place.

"And here I thought you just didn't want me around!"

Jazz made it a joke, defying Bluestreak to take him seriously. Prowl did just that. Within clicks he'd been through every one of their interactions in the last orn. His trained processor made short work of the analysis, and the results brought a wince to his face.

_"__Jazz."_ His private comm was a dismayed and deeply apologetic whisper. _"__I'm so sorry."_

_"__For doing this for Blue?"_ The Ops mech didn't look away from Bluestreak, his arm around the youngling's shoulder turning him slightly so he wouldn't see Prowl's reaction. _"__No worries."_

_"__I owe you an apology nonetheless."_

Jazz glanced over his shoulder, his visor bright. One of the thing Prowl loved about the mech was his ability to look at a grudge, understand it, forgive it and let it go. The hurt in his posture was very real, but it was already fading. He cycled his visor in teasing suggestion.

_"__I'm sure I'll think of a way for you to make it up to me later. For now though…" _The speakers mounted on Jazz's thighs folded out, already emitting a low rumble of sound. He pulsed a little more power to them, moderating the note, and chuckling in satisfaction when the echoes brought twitching pleasure to the door-wings of both Praxians. "Come on, Blue. Why don't you and Prowler show me how this is done?"

* * *

It was almost time for Prowl and Bluestreak to go back on shift by the time they returned to the Ark. If it wasn't for that fact, the three of them would probably still be back at the geode, squeezed together into the resonating crystal chamber, or taking turns to play while the others listened from the cavern above.

Neither Bluestreak nor Jazz rivalled Prowl's skill, but both were learning, and taking all the more pleasure for doing so in company. If Prowl hesitated at first to pass on the secrets of the ancient art form to a non-Praxian, his doubt faded within klicks. Jazz was as much part of his accidental family as the youngling they'd raised between them. The mech might not be Praxian by birth, but the respect and appreciation he showed brought him more credit than many who were. It wasn't as if teaching others was actually banned in any case. It might have raised a few brow-ridges and set a few door-wings quivering, but, even in the Gardens, no one would have stopped him. Now, there was no one left to try.

For once that thought didn't carry the weight of guilt and pain he was so accustomed to. Prowl would have taught his companion this music, even if all the taboos of ancient Praxus had been against it.

The three of them were bright-opticed and their frames vibrated with pleasure and satisfaction as they made their way back towards the lower decks. Prowl and Jazz walked arm in arm, Bluestreak leading the way through the outer hull and back onto familiar territory.

Jazz leaned into Prowl's side, the mech chuckling to himself.

"Jazz?"

"Just wondering what folks'll think we've been up to if they see us like this."

Prowl cycled his optics, not dignifying the comment with a direct response. He pulled Jazz a little tighter, still regretful of the hurt he'd caused.

"Are you going to tell Prime the truth?"

Now Jazz shot him a sidelong look. Prowl shrugged.

"I calculate a seventy-eight percent probability that you would have waited until the end of the orn before tracking us – unless strongly encouraged to do so."

Jazz laughed, rueful and a little amused. "The boss-mech should have known better. What say we keep him guessing a while longer?"

Prowl's small smile answered his partner's. Maybe Jazz was a bad influence on him. Maybe he was just a little peeved by Optimus's prying. Either way, he was more than willing – just this once – to tease their friend and Prime.

"Why not?" he agreed.

Bluestreak glanced back at them. The young mech's faceplates split with a broad smile of their own as his mentors waved him onwards. Nodding, calling out a promise to join them later for energon, the youngling pulled himself up to the deck above and hurried away to catch up with Bumblebee and his scheduled patrol.

The two officers followed briskly, and with perhaps just a tinge of regret. Prowl released his companion as they climbed towards the inhabited deck, the vorns-old mask of decorum falling easily into place. Jazz offered him a servo for the last few yards, but the touch was practical and fleeting. Their online statuses updated at the same moment – Prowl's to 'on duty', Jazz's to 'available if required'. Tilting his helm in farewell, the saboteur headed for the Rec Room, leaving Prowl at the control deck hatch.

Prowl set his door-wings. His expression was inscrutable as he entered to relieve a visibly bored Optimus Prime from his extended monitor duty. Optimus hesitated, just long enough to watch Prowl raise his door-wings into a barrier that actively discouraged conversation

Prowl didn't have to check to know his Prime had departed straight for the Rec Room to quiz Jazz. The private video stream that hit his comms a few minutes later was unexpected confirmation. The affectionate laughter it carried warmed Prowl's frame, just as the presence of Jazz himself had breems before.

He swept assessing optics over the displays in front of him and then settled back in the monitor seat. Willing, for once, to indulge Jazz's distractions as Jazz had indulged his, Prowl relaxed into his companion's comm-channel commentary.

Somewhere in the background of the channel, Jazz's speakers provided a musical soundtrack. The melody was Praxian, a pale echo and reminder of their joyous afternoon. Their physical separation during duty shifts was fleeting, unimportant. The barrier Prowl had thrown between them with his secrecy was no more tangible, and no longer lasting.

Prowl was forgiven, and he was loved.

Through shared optics, Jazz and Prowl watched their Prime puzzle over Jazz's vague, teasing hints – the same music dancing in both their sparks.

* * *

**The End**


End file.
